Questionnaires regarding the perceptions of chemotherapy and its impact on the quality of life (QoL) of their cat were received from owners of 31 cats treated for lymphoma between 2002 and 2006 with COP (cyclophosphamide, vincristine, prednisolone) chemotherapy. The QoL scores prior to the onset of cancer (mean 9.5, range 6-10) were significantly higher than the ratings given after the onset of cancer but before commencement of chemotherapy (mean 3.9, range 1-9.4). The QoL scores during chemotherapy (mean 6.3, range 1-10) were also significantly lower than prior to the onset of cancer, but significantly higher during treatment than prior to starting treatment. Adverse effects were experienced by 27 (87%) cats during the course of chemotherapy. Twenty-five (83%) of clients were happy they treated their cat and 27 owners (87%) would treat another cat. The results suggest that COP chemotherapy is perceived by owners to be tolerated by cats.